Light-Emitting Compound A composition comprising a light-emitting compound having a peak wavelength of at least 650 nm and a material comprising a group of formula (I): wherein Ar1, Ar2 and Ar3 in each occurrence are independently selected from a C6-20 aromatic group and a 6-20 membered heteroaromatic group of C and N ring atoms and at least one of Ar1, Ar2 and Ar3 is a 6-20 membered heteroaromatic group of C and N ring atoms; x, y and z are each independently at least 1; n, m and p are each independently 0 or a positive integer; and R1, R2 and R3 in each occurrence is independently a substituent or a single bond to a polymer chain, wherein the group of formula (I) has no more than 3 single bonds to a polymer chain. The composition may be used in the light-emitting layer of an infrared organic light-emitting device.